Wetsus, Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900CC Leeuwarden, The Netherlands; Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands.
Sub-department Environmental Technology, Wageningen University and Research, P.O. Box 17, 6700AA Wageningen, The Netherlands.
Water Res. 2018 Oct 1;142:10-17. doi: 10.1016/j.watres.2018.05.035. Epub 2018 May 21.
To address the issues of eutrophication and the potential risk of phosphorus (P) shortage, it is essential to remove and recover P from P-containing streams to close this nutrient cycle. Electrochemical induced calcium phosphate (CaP) precipitation was shown to be an efficient method for P recovery. However, the influence of natural organic matter (NOM) is not known for this treatment. In this paper, the behavior of NOM and its effect on CaP precipitation was studied. In contrast to studies where NOM hindered CaP precipitation, results show that the interaction of NOM with CaP improves the removal of P, independent of the types of NOM. The P removal at the average increased from 43.8 ± 4.9% to 58.5 ± 1.2% in the presence of 1.0 mg L NOM. Based on the yellow color of the CaP product, NOM is co-precipitated. The bulk solution pH with and without buffers has totally different effects on the precipitation process. Without buffer, CaP precipitates on the cathode surface in a wide pH range (pH 4.0-10.0). However, the precipitation process is completely inhibited when the bulk solution is buffered at pH 4.0 and 6.0. This is probably due to neutralization of OH by the buffers. Regardless of the presence or absence of NOM and solution pH, the recovered products are mainly amorphous CaP unless the electrolysis time was increased to seven days with 4.0 A m, in which crystalline CaP formed. These findings advance our understanding on the interaction of Ca, P and NOM species for the application of electrochemical method for P recovery from real wastewater.
为了解决富营养化问题和磷（P）短缺的潜在风险，从含磷废水中去除和回收磷以闭合营养循环至关重要。电化学诱导磷酸钙（CaP）沉淀已被证明是一种有效的磷回收方法。然而，对于这种处理方法，天然有机物（NOM）的影响尚不清楚。本文研究了 NOM 的行为及其对 CaP 沉淀的影响。与 NOM 阻碍 CaP 沉淀的研究结果相反，结果表明，NOM 与 CaP 的相互作用可提高磷的去除率，而与 NOM 的类型无关。在 1.0mg/L NOM 的存在下，磷的去除率从 43.8±4.9%提高到 58.5±1.2%。基于 CaP 产物的黄色，NOM 被共沉淀。有和没有缓冲剂的悬浮液 pH 对沉淀过程有完全不同的影响。没有缓冲剂时，CaP 在很宽的 pH 范围（pH 4.0-10.0）内在阴极表面沉淀。然而，当缓冲液将悬浮液的 pH 缓冲在 4.0 和 6.0 时，沉淀过程完全被抑制。这可能是由于缓冲剂中和了 OH。无论存在或不存在 NOM 和溶液 pH，回收的产物主要是无定形 CaP，除非将电解时间延长至七天并施加 4.0 A m，在此条件下形成结晶 CaP。这些发现提高了我们对 Ca、P 和 NOM 物种相互作用的理解，有助于电化学方法从实际废水中回收磷的应用。
